Diagrammatic map of weights and measures in use in 27 Mediterranean and European seaports. Oriented with north to the right. Each port city is represented by a vignette of a prominent local tower and the vignettes are connected by rhumb lines. Manuscript: pen-and-ink (light brown) and watercolors. LC Nautical charts on vellum, 4. Available also through the Library of Congress Web site as a ...